Tourist information offices (TIOs) are an important external information source in the tourists’ decision-making process. Assessing the quality of TIO information services implies measuring both technical quality, that is, the outcome of the service performance, and functional quality, that is, the quality of the whole delivery process. The article presents a methodology to correlate and combine mystery shopping and customer satisfaction research in order to assess the overall performance of TIOs at destination and discusses the effectiveness of this approach compared with a separate application of the two methods. The study is part of a project aimed at providing local authorities and TIO office managers in the mountain areas of Italy and Austria with an integrated and user-friendly tool to monitor the quality of information delivered to tourists both before and during their visit, evaluate the management of information services and make benchmark comparisons in the future.